Under the first year of this grant a mathematical model for conventional tomography was developed, including both linear and axial transverse tomography. This model consists of a 3-dimensional modulation transfer function to describe the tomographic imaging process. Based on this mathematical model, an image enhancement procedure has been proposed which is intended to bring out more clearly the detail in the tomographic plane and hence to increase the clinical utility of these images. This image enhancement procedure has been carried out using a digital image processing system and preliminary results suggest that the processing does increase the clinical information available in tomographic images. During the next year a more thorough study of the optimum enhancement procedures will be completed, and a larger number of tomograms will be studied in an attempt to better evaluate the usefulness of the proposed system. In addition to this investigation, a study related to computerized axial transverse tomography is in progress. This study is concerned with post reconstruction image processing, in an attempt to evaluate the utility of further image processing of the reconstructed image. It is intended to study the utility of color displays, non-linear grey scale modifications, and other imaging techniques in increasing the diagnostic value of the computerized axial transverse scanners.